German Patent Application No. DE 41 12 150 describes an orifice element that has an upper and a lower silicon plate made of monocrystalline silicon. Four injection orifices are arranged in the upper silicon plate, and one large common passthrough orifice is arranged in the lower silicon plate. Recesses that extend from the passthrough orifice to the outer periphery of the lower silicon plate, and thus form air conduits, are introduced into the lower silicon plate. An orifice element of this kind can be used for injection nozzles if a liquid stream is delivered through the injection openings, and a gas stream through the air conduits. The gas stream improves atomization of the liquid stream.
German Patent Application No. DE 42 33 703 describes a cost-effective method for processing the lower silicon plate of an orifice element of this kind. Processing is accomplished by simultaneous chemical etching from both sides of the lower silicon plate.